Quantum Entanglement and Magnetic Polarity

Abstract Atomic ensembles are important quantum resources for the generation, manipulation, and quantum memory of entangled photons. In photonic quantum information based on atom–photon interactions, high‐quality entangled‐photon‐pair sources are essential for realizing quantum information networks consisting of channels to connect the nodes through atomic ensembles. Here, a proof‐of‐concept for controlling polarization‐entangled photon‐pair sources from atomic ensembles by an external magnetic field under a magnetic noise environment is demonstrated. In the unshielded magnetic field, the polarization entangled state of the photon pair could be optimized to the target state by adjusting the magnetic field in an atomic vapor cell. The polarization‐interference fringe, Bell's inequality value, quantum state tomography, and Hong–Ou–Mandel interference of the polarization entangled photon pairs from the cascade‐type 5S 1/2 –5P 3/2 –5D 5/2 transition of 87 Rb according to the direction of the external magnetic field. Accordingly, a magnetic field is found to be a promising means for controlling entangled two‐qubit states based on atom–photon.Abstract Atomic ensembles are important quantum resources for the generation, manipulation, and quantum memory of entangled photons. In photonic quantum information based on atom–photon interactions, high‐quality entangled‐photon‐pair sources are essential for realizing quantum information networks consisting of channels to connect the nodes through atomic ensembles. Here, a proof‐of‐concept for controlling polarization‐entangled photon‐pair sources from atomic ensembles by an external magnetic field under a magnetic noise environment is demonstrated. In the unshielded magnetic field, the polarization entangled state of the photon pair could be optimized to the target state by adjusting the magnetic field in an atomic vapor cell. The polarization‐interference fringe, Bell's inequality value, quantum state tomography, and Hong–Ou–Mandel interference of the polarization entangled photon pairs from the cascade‐type 5S 1/2 –5P 3/2 –5D 5/2 transition of 87 Rb according to the direction of the external magnetic field. Accordingly, a magnetic field is found to be a promising means for controlling entangled two‐qubit states based on atom–photon.

Advanced Quantum TechnologiesJan 29, 20233 citations

On Magnetic Entanglement

Royan Rosche

Sep 1, 20190 citations

Polarization and entanglement in spin systems

G. B. Furman, V. Meerovich, Vladimir Sokolovsky

We established important relationships between entanglement measures and the order parameter (spin polarization) in nuclear spin systems controlled by the nuclear magnetic resonance (NMR) technique. Since spin polarization can be easily manipulated by the NMR technique, experimentalists are presented with an opportunity to study the dynamic properties of entanglement, i.e., the creation and evolution of entangled states. Our approach may constitute the basis for researching the relations between the entanglement measures and measurable parameters of order in other quantum systems.We established important relationships between entanglement measures and the order parameter (spin polarization) in nuclear spin systems controlled by the nuclear magnetic resonance (NMR) technique. Since spin polarization can be easily manipulated by the NMR technique, experimentalists are presented with an opportunity to study the dynamic properties of entanglement, i.e., the creation and evolution of entangled states. Our approach may constitute the basis for researching the relations between the entanglement measures and measurable parameters of order in other quantum systems.

arXiv:0810.4388Oct 24, 20080 citations

Entanglement in quantum spin systems

Jeffrey Scott Pratt

Jan 1, 20050 citations

Sharing polarization within quantum subspaces

Muhammad Sabieh Anwar, Jonathan A. Jones, Simon B. Duckett

Given an ensemble of $n$ spins, at least some of which are partially polarized, we investigate the sharing of this polarization within a subspace of $k$ spins. We assume that the sharing results in a pseudopure state, characterized by a single purity parameter which we call the bias. As a concrete example we consider ensembles of spin- $1∕2$ nuclei in liquid-state nuclear magnetic resonance systems. The shared bias levels are compared with some current entanglement bounds to determine whether the reduced subspaces can give rise to entangled states.Given an ensemble of $n$ spins, at least some of which are partially polarized, we investigate the sharing of this polarization within a subspace of $k$ spins. We assume that the sharing results in a pseudopure state, characterized by a single purity parameter which we call the bias. As a concrete example we consider ensembles of spin-$1∕2$ nuclei in liquid-state nuclear magnetic resonance systems. The shared bias levels are compared with some current entanglement bounds to determine whether the reduced subspaces can give rise to entangled states.

arXiv:quant-ph/0509036Physical Review AFeb 13, 20062 citations

Magnetic shielding of quantum entanglement states

O. M. Del Cima, D. H. T. Franco, M. M. Silva

arXiv:1803.01241Quantum Studies Mathematics and FoundationsAug 24, 201811 citations

Given an ensemble of

n

spins, at least some of which are partially polarized, we investigate the sharing of this polarization within a subspace of

k

spins. We assume that the sharing results in a pseudopure state, characterized by a single purity parameter which we call the bias. As a concrete example we consider ensembles of spin-

1∕2

nuclei in liquid-state nuclear magnetic resonance systems. The shared bias levels are compared with some current entanglement bounds to determine whether the reduced subspaces can give rise to entangled states.